Graphene-infused paint for automotive fluid pipes

Abstract

A coated metal pipe for use as an automotive fluid carrying pipe, comprising a pipe formed with a circular cross-sectional shape, an intermediate layer applied over the pipe, and an exterior paint topcoat incorporating a graphene derivative applied over the intermediate layer to provide excellent corrosion resistance in addition to chemical and abrasion resistance.

Description

[Technical field]

[0001] The present invention discloses an automotive fluid transport pipe and associated manufacturing method to provide superior corrosion / wear resistance. The pipe can be constructed of either low carbon steel, which may be nickel plated in a welded single wall pipe, extruded aluminum, or low carbon steel, which may be copper plated in a brazed double wall pipe. The middle layer can include either zinc / aluminum alloy, electroplated zinc, electroplated Zn / Ni, or molten aluminum. The top coat of the uppermost layer consists of a water-based or organic solvent-based paint with graphene dispersed in the paint.

[0002] The topcoat can include either an epoxy paint, an epoxy ester paint, or a polyvinyl difluoride paint. Graphene dispersed in the paint system can provide a percolation network for enhanced corrosion resistance as well as chemical and abrasion resistance when subjected to standard automotive test conditions. CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Patent Application No. 18 / 110,584, filed February 16, 2023, which claims the benefit of U.S. Patent Application No. 63 / 311,111, filed February 17, 2022. These U.S. applications are incorporated by reference herein in their entireties, including any drawings. [Background technology]

[0003] Fluid-carrying lines within a vehicle perform the important function of carrying fuel, brake fluid, and transmission oil coolant during operation of the vehicle. Transmission oil cooling (TOC) or fuel fill lines contain welded tubing made from low carbon steel and are susceptible to corrosion, which can result in the safe operation of the vehicle being compromised.

[0004] To reduce vulnerability to corrosion, zinc-aluminum alloys, electroplated zinc, electroplated zinc / nickel or molten aluminum can be applied directly to the steel pipe. For example, a zinc layer or electroplated zinc acts as a sacrificial coating, thus protecting the steel pipe underneath. The topcoat can be an organic solvent-based paint or a water-based system and in some cases may require a primer for adhesion to the underlayer.

[0005] As is well known, graphene is a two-dimensional planar nanomaterial that contains sp2 bonded carbon atoms packed into a honeycomb lattice. Many of the material properties that make graphene advantageous, such as high tensile strength, high chemical resistance, and high thermal and electrical conductivity, stem from the unique bonding structure of planar graphene. However, utilizing graphene on a macroscopic scale for applications such as the automotive industry remains a challenge.

[0006] Given the above background, US Patent No. 5,399,933 to Kerin, Jr. et al. teaches coated metal pipes, including either single wall or double wall pipes formed in a circular cross-sectional shape, for use as automotive fluid-transport pipes. An intermediate primer layer is applied over the pipe. A polyamide mixed with graphene powder is then applied over the intermediate layer.

[0007] Crain's US Patent No. 5,999,633 is directed to a fuel system component having a polymer composition that includes functionalized graphene sheets. In one embodiment, the fuel system can include multiple layers secured to the fuel system component. The fuel system component is in direct contact with one or more fuels or provides one or more paths to ground from one or more second components that are in direct contact with the flowing fuel. Each first layer can include any of metal, fiber, and woven materials, and each second layer can include one or more polymer compositions and a fully exfoliated single sheet of graphene having a carbon to oxygen molar ratio of at least 50:1.

[0008] Patent Document 3 teaches an anti-rust paint for hydraulic pipes and a related preparation method. The paint includes a resin, a graphene aqueous dispersion, a pigment filler, an auxiliary agent, and a solvent.

[0009] Patent Document 4 teaches a graphene-modified epoxy resin anti-rust coating comprising, by weight, 70-80 parts water-based epoxy resin, 4-7 parts cumene hydroeroxide, 10-18 parts graphene, 2.5-4.5 parts hexamethylene diisocyanate biuret, 2.4-3.6 parts ethylenediaminetetraacetic acid disodium salt, 5-9 parts methylbenzotriazole, 7-10 parts nonylphenol polyoxyethylene ether, 5-8 parts phytase, 4-6 parts wax powder, 4-13 parts polysulfone resin and 4-6 parts copper sulfate. The graphene-modified epoxy resin anti-rust coating has high abrasion resistance, high temperature resistance, water resistance and chemical corrosion resistance, and the adhesive strength between the coating and the base surface is enhanced, and the curing speed at all temperatures is improved.

[0010] A further example of the prior art is shown by Picco et al.'s U.S. Patent No. 5,399,633, which discloses an automotive fluid pipe configured to carry either gasoline / diesel fuel or hydraulic fluids and constructed from metal having a coating of aluminum onto which a layer of polyamide 12 is extrusion coated to improve the wear and corrosion resistance of the pipe.

[0011] Berger et al., US Patent No. 6,363,333 teaches a method of coating a metal article by coating the metal surface with a polymer or a two-component system that reacts to form a polymer after application to the metal surface. The composition contains 70 to 2700 milliequivalents / kg of olefinic double bonds, which provide stronger adhesion and improved corrosion resistance.

[0012] Also, Patent Document 7 to Kawai teaches a coated metal pipe, in which the multi-layer coating includes a chemical conversion layer and a primer layer, and the primer layer further includes polyamideimide and at least one additive component selected from polyamide, a fluororesin, a silane coupling agent, and an epoxy resin.

[0013] Other pipe systems are known in the art that utilize PVDF (polyvinylidene fluoride) paints and related water-based coatings to provide a pure thermoplastic fluoropolymer with multiple coating advantages, including non-reactive, solvent and acid resistance, and lower density compared to similar fluoropolymers. One example is described in Usui's U.S. Patent No. 5,333,363, which teaches a resin coating with corrosion resistance, weather resistance, and chemical resistance, durability, and high heat resistance. A steel pipe is formed, optionally with a copper layer. At that point, a zinc or zinc / nickel plating layer is formed on the outer circumferential surface of the steel pipe, and a chromate coating containing a trivalent chromium compound is formed on the zinc or zinc / nickel plating layer. If necessary, at least one layer of a resin selected from the group consisting of polyvinyl fluoride, polyvinylidene fluoride (PVDF), polypropylene, polyethylene, and polyamide resins is formed through a primer. Finally, US Patent No. 5,399,323 to Hsich teaches a coated metal tube construction comprising a metal tube and an inner layer of a first polymeric material bonded to the tube to provide corrosion protection. The first polymeric material has high crystallinity, a damping coefficient of less than 0.05, and a flexural modulus of at least 100 MPa. An outer layer of a second polymeric material is extruded around the inner layer to absorb impact energy and eliminate mechanical vibration and acoustic noise. The second polymeric material comprises a multiphase polymer having a damping coefficient of at least 0.05 and a flexural modulus of less than 50 MPa, and at least one polymeric component with a glass transition temperature below room temperature. [Prior art documents] [Patent documents]

[0014] [Patent Document 1] U.S. Pat. No. 10,625,487 [Patent Document 2] U.S. Patent No. 9,810,350 [Patent Document 3] China Patent Publication No. 104789092 [Patent Document 4] China Patent Publication No. 105969069 [Patent Document 5] U.S. Patent No. 6,915,820 [Patent Document 6] U.S. Pat. No. 9,556,358 [Patent Document 7] US Patent Application Publication No. 2018 / 0119871 [Patent Document 8] U.S. Patent No. 6,500,565 [Patent Document 9] U.S. Patent No. 6,589,617 Summary of the Invention [Problem to be solved by the invention]

[0015] The present invention relates to utilizing the excellent material properties of graphene together with suitable binders to produce high quality coatings as topcoats for premium automotive industrial scale fluid transport pipes. More specifically, the present invention discloses an automotive fluid transport pipe and associated manufacturing method to provide excellent corrosion / abrasion resistance. [Means for solving the problem]

[0016] The tubes can be constructed of either low carbon steel, which may be nickel plated with welded single wall tubes, extruded aluminum, or low carbon steel, which may be copper plated with brazed double wall tubes. The middle layer can include either a zinc / aluminum alloy, electroplated zinc, electroplated zinc / nickel, or molten aluminum. The top coat of the uppermost layer consists of a water-based or organic solvent-based paint with graphene powder dispersed in the paint.

[0017] In certain examples, the topcoat may be a solvent-based epoxy paint, or an epoxy ester paint or polyvinyl difluoride paint with graphene derivatives dispersed therein. The graphene derivatives may include, but are not limited to, single layer graphene, few layer graphene, graphene oxide, reduced graphene oxide, and functionalized graphene. The above paint system is applied to the tube by either a spray application process, a dip application process, or a flow coat application process, followed by a curing process with a specific baking schedule. The graphene derivatives dispersed in the paint system can provide a percolation network for corrodible elements, thereby providing improved corrosion resistance.

[0018] In another particular example, the topcoat may require an additional primer layer to adhere to the intermediate metal layer on the tube. The primer may be an inorganic metal-based sacrificial layer that provides additional corrosion resistance to the coating layer below, or an epoxy-based primer for topcoat adhesion. The primer may be applied to the tube by either a spray, dip, or flow coat application process, and may require an additional curing process with a specific baking schedule. Graphene may also be dispersed in this primer layer to improve corrosion resistance. [Brief description of the drawings]

[0019] When read in conjunction with the following detailed description, reference is made to the accompanying drawings, in which like numerals refer to like parts throughout the several views, and in which:

[0020] [Figure 1] FIG. 1 is a longitudinal cross-sectional view of a wall segment of an automotive fluid transport pipe according to a first non-limiting embodiment, showing a first layer of low carbon steel, which may be nickel plated for a welded single wall pipe or copper plated for a brazed double wall pipe, with an intermediate zinc / aluminum alloy and an outer or top coat of graphene mixed paint.

[0021] [Figure 1A] 2 is a cross-sectional view of an end portion of the automotive fluid transport pipe of FIG. 1.

[0022] [Diagram 2] FIG. 2 is a longitudinal cross-sectional view of a wall segment of an automotive fluid transport pipe according to a second non-limiting embodiment, showing a first layer of low carbon steel, which may be nickel plated for a welded single wall pipe or copper plated for a brazed double wall pipe, with an intermediate electroplated zinc, and an outer or top coat of graphene mixed paint.

[0023] [Figure 2A] 3 is a cross-sectional view of an end portion of the automotive fluid transport pipe of FIG. 2.

[0024] [Diagram 3] FIG. 13 is a longitudinal cross-sectional view of a wall segment of an automotive fluid transport pipe according to a third non-limiting embodiment, showing a first layer of low carbon steel, which may be nickel plated for a welded single wall pipe or copper plated for a brazed double wall pipe, with an intermediate molten aluminum, and an outer or top coat of graphene mixed paint.

[0025] [Figure 3A] 4 is a cross-sectional view of an end portion of the automotive fluid transport pipe of FIG. 3.

[0026] [Figure 4] FIG. 13 is a longitudinal cross-sectional view of a wall segment of an automotive fluid transport pipe according to a fourth non-limiting embodiment, showing a first layer of low carbon steel, which may be nickel plated for a welded single wall pipe or copper plated for a brazed double wall pipe, with an intermediate electroplated zinc / nickel and an outer or top coat of graphene mixed paint.

[0027] [Figure 4A] 5 is a cross-sectional view of an end portion of the automotive fluid transport pipe of FIG. 4.

[0028] [Diagram 5]FIG. 13 is a longitudinal cross-sectional view of a wall segment of an automotive fluid transport pipe according to a fifth non-limiting embodiment, showing a base layer of extruded aluminum and an outer or top coat of paint mixed with graphene.

[0029] [Figure 5A] 6 is a cross-sectional view of an end portion of the automotive fluid transport pipe of FIG. 5. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] With non-limiting reference to the accompanying drawings, the present invention teaches automotive fluid transport pipes of various compositions coated with multi-layer or single-coat systems, each of which is corrosion-resistant, abrasion-resistant, and impact-resistant. The present invention also teaches associated methods for manufacturing any of the pipes that are the subject of the system, article, or assembly.

[0031] In each of the variations disclosed, the tube comprises either low carbon steel which may be nickel plated with a welded single wall tube, extruded aluminum, or low carbon steel which may be copper plated with a brazed double wall tube. The middle layer may comprise either a zinc / aluminum alloy, electroplated zinc, electroplated zinc / nickel, or molten aluminum. The uppermost top coat consists of a water-based or organic solvent-based paint with graphene powder dispersed in the paint.

[0032] Referring initially to Figure 1, a longitudinal cross-section of a wall segment of an automotive fluid transport pipe according to a first non-limiting embodiment is shown generally at 10. As further shown in the end cross-sectional view of Figure 1A, the pipe shows a first layer 12 of low carbon steel, which may be nickel plated for a welded single layer pipe or copper plated for a brazed double layer pipe. Also shown is an intermediate zinc / aluminum alloy 14 and an outer or top coat 16 of paint mixed with graphene.

[0033] As described herein, the topcoat can include an anti-corrosive epoxy paint or an epoxy ester paint or a polyvinyl difluoride, and optionally a graphene derivative is dispersed in the paint. As a non-limiting example, a graphene derivative powder dispersed in a paint system can provide a percolation network to enhance the barrier resistance.

[0034] It is also envisioned that the above-mentioned epoxy-based paint or polyvinyl difluoride-based paint is applied to the tube by a dip-coating process, a spray-coating process or a flow-coating process, followed by a curing process with a specific baking schedule. According to any application process and method used, the use of epoxy-based paint or polyvinyl difluoride-based paint-based topcoat with dispersed graphene derivatives can exhibit excellent corrosion resistance as well as chemical and abrasion resistance when exposed to standard automotive test conditions.

[0035] It is also envisioned that the epoxy-based paints or polyvinyl difluoride-based paints mentioned above may require an additional primer layer to improve adhesion of the paint topcoat to the underlying intermediate metal layer. The primer may be an inorganic metal-based sacrificial layer that provides additional corrosion resistance to the underlying metal tube, or it may be an epoxy-based primer for topcoat adhesion. The primer may be applied to the tube by either a spray, dip, or flow coat application process, and may require an additional curing process with a specific baking schedule. Graphene derivatives may also be dispersed in this primer layer to improve corrosion resistance.

[0036] 2 and the corresponding end cross-sectional view in FIG 2A, a wall segment of an automotive fluid transport pipe according to a second non-limiting embodiment is generally indicated at 20 and shows a first layer 22 of low carbon steel, which may be a welded single wall pipe, nickel plated, or a copper plated brazed double wall pipe, an intermediate layer 24 of electroplated zinc, and an outer or top coat 26 of paint mixed with graphene (typically any type of graphene derivative as previously described herein). The description of the alternative graphene materials is repeated from the description of FIG 1 for this and all other embodiments described herein.

[0037] 3 is a longitudinal cross-sectional view of a wall segment of an automotive fluid transport pipe generally at 30 according to a third non-limiting embodiment, showing a first layer 32 of low carbon steel, which may be a welded single wall pipe, nickel plated, or a copper plated brazed double wall pipe, onto which is applied an intermediate layer 34 of molten aluminum, and an outer or top coat 36 of graphene-infused paint. FIG 3A shows an end cross-sectional view of the automotive fluid transport pipe of FIG 3.

[0038] 4 is a longitudinal cross-sectional view of a wall segment of an automotive fluid transport pipe generally at 40 according to a fourth non-limiting embodiment, showing a first layer 42 of low carbon steel, which may be a welded single wall pipe, nickel plated, or a copper plated brazed double wall pipe, onto which is applied an intermediate layer 44 of electroplated zinc / nickel, and an outer or top coat 46 of graphene-infused paint. FIG. 4A shows an end cross-sectional view of the automotive fluid transport pipe 40 of FIG.

[0039] Proceeding to Figure 5, a longitudinal cross-sectional view, generally at 50, of an automotive fluid transport pipe wall segment according to a fifth non-limiting embodiment is provided, showing a base layer of extruded aluminum 52 and an outer or top coat of graphene-infused paint 54. Finally, Figure 5A shows an end cross-sectional view of the automotive fluid transport pipe 50 of Figure 5.

[0040] Having described the invention, other and additional preferred embodiments will become apparent to those skilled in the art to which the invention pertains without departing from the scope of the appended claims. This may further include, but is not limited to, a tube constructed of either copper plated low carbon steel, low carbon steel, stainless steel, or aluminum. The invention further contemplates other application processes besides extrusion for applying the outer polymer layer to the tube.

[0041] Among related variations, this can include the use of any suitable forming process, including but not limited to extrusion, other injection molding techniques to form the desired combination of an outer polyamide / graphene powder layer and an intermediate corrosion protection layer around an inner metal tube.

[0042] Having described the present invention, other and additional preferred embodiments will become apparent to those skilled in the art to which the present invention pertains without departing from the scope of the appended claims. It is further understood that the detailed description and drawings are supportive of this disclosure, the scope of which is defined by the claims. Although some of the best modes and other embodiments for carrying out the teachings set forth in the claims have been described in detail, there are various alternative designs and embodiments for carrying out the disclosure as defined in the appended claims.

[0043] Furthermore, it is understood that the foregoing disclosure is not intended to limit the disclosure to the exact form or particular field of use disclosed. Thus, various alternative embodiments and / or modifications to the disclosure, whether expressly described or implied herein, are contemplated in light of the present disclosure. Having thus described an embodiment of the present disclosure, those skilled in the art will recognize that changes can be made in form and detail without departing from the scope of the present disclosure. Thus, the present disclosure is limited only by the claims.

[0044] In the foregoing specification, the disclosure has been described with reference to specific embodiments. However, as will be appreciated by those skilled in the art, the various embodiments disclosed herein may be modified or embodied in various other ways without departing from the spirit and scope of the disclosure. Thus, this description should be considered as illustrative and is intended to teach those skilled in the art how to make and use the various embodiments of the disclosure. It should be understood that the forms of the disclosure shown and described herein should be taken as representative embodiments. The elements, materials, processes or steps typically shown and described herein may be replaced with equivalent elements, materials, processes or steps. Also, certain features of the disclosure may be utilized independently of the use of other features, all of which will be apparent to those skilled in the art after benefiting from this description of the disclosure. The terms "comprising," "including," "mixed," "consisting of," "having," "is," and the like, used to describe and claim the disclosure, are intended to be interpreted in a non-exclusive manner, i.e., allowing for the presence of items, components or elements not expressly described. Reference to the singular should be interpreted to relate to the plural as well.

[0045] Furthermore, the various embodiments disclosed herein should be construed in an illustrative and explanatory sense, and should not be construed as limiting the present disclosure in any way. All connector expressions (e.g., attached, secured, coupled, connected, etc.) are used only to aid the reader's understanding of the present disclosure, and do not create limitations with respect to the position, orientation, or use of the systems and / or methods specifically disclosed herein. Thus, connector expressions, if any, should be interpreted broadly. Also, such connector expressions do not necessarily imply that two elements are directly connected to each other.

[0046] Additionally, without limitation, all numerical terms such as "first," "second," "third," "primary," "secondary," "main," or any other general and / or numerical terms should be construed merely as identifiers to aid the reader in understanding the various elements, embodiments, variations and / or modifications of the present disclosure, and in particular do not create any limitation as to the order or priority of any element, embodiment, variation and / or modification relative to other elements, embodiments, variations and / or modifications.

[0047] It will also be understood that one or more of the elements shown in the drawings / diagrams may be implemented in a more separate or integrated manner, or even removed or rendered inoperative in some cases, as may be useful according to a particular application. Additionally, the signal hatches in the drawings / diagrams are to be considered as illustrative only and not limiting, unless otherwise noted.

Claims

1. 1. A coated metal pipe for use as a fluid transport pipe for an automobile, comprising: A tube formed into a circular cross-sectional shape; an intermediate layer applied onto the tube; an outer paint coating incorporating a graphene derivative applied over the intermediate layer, which provides excellent corrosion resistance in addition to chemical and abrasion resistance; A coated metal pipe comprising:

2. 10. The coated metal tube of claim 1, wherein the tube further comprises one of low carbon steel, nickel plated, or copper plated low carbon steel.

3. 10. The coated metal tube of claim 1, wherein the intermediate layer further comprises any of a corrosion-inhibiting zinc / aluminum alloy, electroplated zinc, electroplated zinc / nickel, or molten aluminum applied directly onto the tube.

4. The coated metal tube of claim 1 , further comprising: the graphene derivative being mixed with the outer paint coating as a powder.

5. 10. The coated metal pipe of claim 1, wherein the outer paint coating further comprises an anti-corrosive solvent-based epoxy paint, an epoxy ester paint, or a polyvinyl difluoride paint.

6. The coated metal pipe of claim 1 , wherein the outer paint coating further comprises a percolation network for providing improved barrier resistance.

7. 10. The coated metal pipe of claim 1, wherein the outer paint coating further comprises a water-based or solvent-based paint system applied to the pipe by either a spray-applying, flow-applying, or dip-applying type process followed by a curing process using a specific baking schedule.

8. 2. The coated metal pipe of claim 1, wherein the outer coating further comprises a primer layer under the topcoat coating to improve adhesion, the primer layer including but not limited to inorganic metal-based or epoxy-based.

9. The coated metal tube of claim 8 , further comprising: the graphene derivative being mixed with the primer layer as a powder.

10. 9. The coated metal tube of claim 8, wherein the primer further comprises a percolation network for providing improved barrier resistance.

11. 10. The coated metal pipe of claim 8, wherein the primer further comprises a water-based or solvent-based primer system applied to the pipe by either a spray-applying, flow-applying, or dip-applying type process, which may be followed by a curing process with a specific baking schedule.

12. 1. A coated metal pipe for use as a fluid transport pipe for an automobile, comprising: an extruded aluminum tube formed into a circular cross-sectional shape; an outer paint coating having a graphene derivative applied over the intermediate layer, the outer paint coating providing excellent corrosion resistance in addition to chemical and abrasion resistance; A coated metal pipe comprising:

13. 13. The coated metal tube of claim 12, further comprising: the graphene derivative being mixed with the outer paint coating as a powder.

14. 13. The coated metal pipe of claim 12, wherein the outer paint coating further comprises an aluminum-rich anti-rust epoxy paint, an epoxy ester paint, or a polyvinyl difluoride paint.

15. 13. The coated metal pipe of claim 12, wherein the outer paint coating further comprises a percolation network for providing improved barrier resistance.

16. 13. The coated metal tube of claim 12, wherein the outer paint coating further comprises either an epoxy, an epoxy ester based paint, or a polyvinyl difluoride system applied to the tube by either a spray application, flow application, or dip application type process followed by a curing process with a specific baking schedule.

17. 13. The coated metal pipe of claim 12, wherein the outer paint coating further comprises a lower primer layer to improve adhesion, the primer layer including but not limited to inorganic metal-based or epoxy-based.

18. 20. The coated metal tube of claim 17, wherein the lower primer layer further comprises a water-based or solvent-based primer system, which is applied to the tube by either a spray-, flow-, or dip-type process, followed by a hardening process of the tube according to a specific firing schedule.

19. 20. The coated metal tube of claim 17, further comprising: the graphene derivative being mixed with the primer layer as a powder.

20. 20. The coated metal tube of claim 17, wherein the primer layer further comprises a percolation network for providing improved barrier resistance.

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